19939613 has 2 divisors, whose sum is σ = 19939614. Its totient is φ = 19939612.

The previous prime is 19939583. The next prime is 19939631. The reversal of 19939613 is 31693991.

19939613 = 3157² + 3158².

Together with next prime (19939631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9972964 + 9966649 = 3158^2 + 3157^2 .

It is a cyclic number.

It is not a de Polignac number, because 19939613 - 2⁸ = 19939357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19939693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9969806 + 9969807.

It is an arithmetic number, because the mean of its divisors is an integer number (9969807).

Almost surely, 2^19939613 is an apocalyptic number.

19939613 is the 3158-th centered square number.

It is an amenable number.

19939613 is a deficient number, since it is larger than the sum of its proper divisors (1).

19939613 is an equidigital number, since it uses as much as digits as its factorization.

19939613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39366, while the sum is 41.

The square root of 19939613 is about 4465.3793791793. The cubic root of 19939613 is about 271.1682936817.

The spelling of 19939613 in words is "nineteen million, nine hundred thirty-nine thousand, six hundred thirteen".